''Caladenia rosella'', commonly known as the rosella spider orchid is a plant in the orchid family

Orchidaceae Orchids are plants that belong to the family Orchidaceae (), a diverse and widespread group of flowering plants with blooms that are often colourful and fragrant. Along with the Asteraceae, they are one of the two largest families of flowering ...

and is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

to south-eastern Australia. It is a ground orchid with a single hairy leaf and a single scented pink flower. Although it may have had a wider distribution in the past, the total number of plants in 2000 was estimated to be 120 in four populations in

Victoria Victoria most commonly refers to: * Victoria (Australia), a state of the Commonwealth of Australia * Victoria, British Columbia, provincial capital of British Columbia, Canada * Victoria (mythology), Roman goddess of Victory * Victoria, Seychelle ...

. There is a single record from

New South Wales ) , nickname = , image_map = New South Wales in Australia.svg , map_caption = Location of New South Wales in AustraliaCoordinates: , subdivision_type = Country , subdivision_name = Australia , established_title = Before federation , es ...

but the orchid is classified as "extinct" in that state.

Description

''Caladenia rosella'' is a terrestrial,

perennial A perennial plant or simply perennial is a plant that lives more than two years. The term ('' per-'' + '' -ennial'', "through the years") is often used to differentiate a plant from shorter-lived annuals and biennials. The term is also wid ...

deciduous In the fields of horticulture and Botany, the term ''deciduous'' () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed leaves, usually in the autumn; to the shedding of petals, ...

, herb with an underground

tuber Tubers are a type of enlarged structure used as storage organs for nutrients in some plants. They are used for the plant's perennation (survival of the winter or dry months), to provide energy and nutrients for regrowth during the next growin ...

and a single erect, hairy leaf, long and wide. A single pale or bright pink flower wide is borne on a stalk tall. The

sepal A sepal () is a part of the flower of angiosperms (flowering plants). Usually green, sepals typically function as protection for the flower in bud, and often as support for the petals when in bloom., p. 106 The term ''sepalum'' was coine ...

s and petals have long, dark, thread-like tips covered with

glandular In animals, a gland is a group of cells in an animal's body that synthesizes substances (such as hormones) for release into the bloodstream (endocrine gland) or into cavities inside the body or its outer surface (exocrine gland). Structure De ...

hairs. The

dorsal Dorsal (from Latin ''dorsum'' ‘back’) may refer to: * Dorsal (anatomy), an anatomical term of location referring to the back or upper side of an organism or parts of an organism * Dorsal, positioned on top of an aircraft's fuselage * Dorsal c ...

sepal is erect, long and wide. The

lateral Lateral is a geometric term of location which may refer to: Healthcare *Lateral (anatomy), an anatomical direction * Lateral cricoarytenoid muscle * Lateral release (surgery), a surgical procedure on the side of a kneecap Phonetics *Lateral co ...

sepals are long, wide and spread widely, turning slightly downwards. The petals are long, wide and arranged like the lateral sepals. The labellum is long, wide and pale pink near its base but darker pink near its edges and tip. The sides of the labellum have linear teeth up to long and the tip of the labellum is curled under. There are four or six rows of pink calli along the centre of the labellum. In warm weather the flowers have a musky scent. Flowering occurs from August to September.

Taxonomy

''Caladenia rosella'' was first formally described in 1988 by Geoffrey Carr from a specimen collected near

Hurstbridge Hurstbridge is a town in Victoria, Australia, 28 km north-east of Melbourne's Central Business District, located within the Shire of Nillumbik local government area. Hurstbridge recorded a population of 3,554 at the 2021 census. Hurstbri ...

and the description was published in '' Muelleria''. The specific epithet (''rosella'') is the diminutive form of the

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

word ''rosa'' meaning "of roses", hence "rose-pink" referring to the colour of the flowers of this orchid.

Distribution and habitat

The rosella spider orchid occurs in areas to the near-north of

Melbourne Melbourne ( ; Boonwurrung/Woiwurrung: ''Narrm'' or ''Naarm'') is the capital and most populous city of the Australian state of Victoria, and the second-most populous city in both Australia and Oceania. Its name generally refers to a met ...

where it grows in woodlands and low forests. It was formerly more widespread in central and western Victoria and in nearby parts of New South Wales.

Ecology

The most likely pollinator of ''C. rosella'' is a male thynnid wasp but a small bee in the genus '' Neoproctus'' has been shown to also be a pollinator of this species.

Conservation

The numbers of the rosella orchid have declined because of habitat loss and fragmentation so that by 2000, only 120 plants in four populations near Melbourne were known. The species is classified as "extinct" in New South Wales, as "endangered" under the Australian Government ''

Environment Protection and Biodiversity Conservation Act 1999 The ''Environment Protection and Biodiversity Conservation Act 1999'' (Cth) is an Act of the Parliament of Australia that provides a framework for protection of the Australian environment, including its biodiversity and its natural and cult ...

'' and as "endangered" under the Victorian

Flora and Fauna Guarantee Act 1988 The ''Flora and Fauna Guarantee Act 1988'', also known as the ''FFG Act'', is an act of the Victorian Government designed to protect species, genetic material and habitats, to prevent extinction and allow maximum genetic diversity within the Au ...

. The main threats to the species are weed invasion, trampling during recreational activities and grazing by rabbits.

References

{{Taxonbar, from=Q9673933

rosella Rosellas are in a genus that consists of six species and nineteen subspecies. These colourful parrots from Australia are in the genus ''Platycercus''. ''Platycercus'' means "broad-tailed" or "flat-tailed", reflecting a feature common to the ...

Plants described in 1988 Endemic orchids of Australia Orchids of Victoria (Australia)